Vaccines remain one of the most cost-beneficial medical interventions. The Hepatitis Viruses Section (HVS) has been instrumental in the development of licensed vaccines for the prevention of hepatitis A and hepatitis B. Although inactivated HAV vaccines are licensed and commercially available, there remains a need for a live attenuated HAV vaccine for administration in developing countries where the cost and logistics of administering an inactivated vaccine are prohibitive. The HVS in collaboration with SmithKline Beecham, Rixensart, Belgium, has developed several candidate live attenuated HAV vaccines. In addition, the HVS has developed a candidate recombinant hepatitis E vaccine that is highly promising and that is currently in clinical trials.A recent advance in vaccine development was the discovery that naked viral DNA can serve as a vaccine when administered to animals. The HVS is studying the technology of DNA vaccines with a model system based upon hepatitis B virus (HBV) vaccine, a vaccine with which the HVS has had extensive experience. We are currently testing the efficacy of an immunostimulant (CpG) as an adjuvant for DNA vaccines, as well as protein vaccines. In addition, the utility of DNA vaccines for the control of hepatitis C virus (HCV) is being explored. These studies were extended to non-human primates (rhesus monkeys). A DNA vaccine proved to be highly immunogenic in mice and rhesus monkeys and we have proceeded to chimpanzees, which can be challenged with live HCV. - Hepatitis viruses, vaccines